My `83 TD wont shutoff with the key. I have vacuum from the key switch to the fuel shutoff solenoid on the IP. I measure about 3 inches of vacuum from the switch vacuum line to the shutoff with the key switch in the off position. When I connect my vacuum hand pump to the shutoff line , it takes about 5-6 inches to shut the engine down. There is no oil in the shutoff valve line and it holds the vacuum fine. I guess my question is is the vacuum from the key switch less than specs (I know it is less than what this valve needs) or is the shutoff valve requiring more vacuum than it should to shut down the engine (possible sticky or binding valve shutoff valve)? Thanks!!

__________________
1980 300D, 1984 300d Euro,

Depending upon your altitude your vacuum system should be reading around 20 inches. You're way low. Test it at the pump. You probably have a leak somewhere.

__________________
1977 300d 70k--sold 08
1985 300TD 185k+
1984 307d 126k--sold 8/03
1985 409d 65k--sold 06
1984 300SD 315k--daughter's car
1979 300SD 122k--sold 2/11
1999 Fuso FG Expedition Camper
1993 GMC Sierra 6.5 TD 4x4
1982 Bluebird Wanderlodge CAT 3208--Sold 2/13

i agree ,you need to check that your getting at least 20 inches of vacume from pump before going further in search.if the pump is ok then go and check the rest of system.

__________________
95 e320,87 sdl,79 300sd

Thanks for the responses. You guys nailed it. I`m getting a solid 20 inches out of the pump (it should- I rebuilt it). At the taps on the line from the pump to the booster I get like 5 inches. I think the check valve in the booster line that the 2 vacuum taps come off of is clogged or bad. Thanks again.

__________________
1980 300D, 1984 300d Euro,

Most of the minor vacuum lines on my '85 300D are cracked and split. ALL of mine are going to be replaced as I start working under the hood.

Vacuum hose is sure cheap too.

__________________
1985 300D 198K sold
1982 300D 202K
1989 300E 125K
1992 940T

"If you dont have time to do it safely, you dont have time to do it"

"The democracy will cease to exist when you take away from those who are willing to work and give to those who would not."

When I dosconnected the Brown Vac Tubing from the Vacuum Shutoff on the IP on my Car 1 month ago and hooked up a Vac Gauge I got 20 inches when the key was turned to the shutoff position.

__________________
84 300D, 82 Volvo 244Gl Diesel

If your Vacuum Pump is good and you have no other Vacuum Leaks:

This is the other Vacuum Switch on your Steering Wheel Lock. The hoses there could be leaking or the Switch Itself could be bad.

Attached Thumbnails

 

__________________
84 300D, 82 Volvo 244Gl Diesel

are you having trouble with doors locking ,hard brakes etc,maybe booster line is cracked or maybe booster is leaking off vacume,i just went through my vac system to track down leak,start with biggest suspects first then narrow down by system.it can be tedious but do a search here for vacume shuttoff there is a nice diagram there of the whole system.

__________________
95 e320,87 sdl,79 300sd